1. Field of the Invention
The present invention relates to a bonding method and a bonding device in which a bonding member is used to bond a first member to a second member.
2. Related Background Art
In a magnetic head manufacturing process, the bonding between a magnetic head slider electrode and a flexure electrode is effected by soldering using a solder ball. To be more specific, the two electrodes are arranged at an angular interval of 90 degrees, and a solder ball is arranged between the electrodes. The ball is melted by heat radiation or the like to effect electrical bonding between these electrodes. In the following, a conventional solder ball soldering device will be described with reference to the drawings.
FIG. 9 is a partial sectional view of a suction nozzle for a soldering process using a conventional soldering device 300. In FIG. 9, reference numeral 309 indicates a slider formed substantially as a parallelepiped, and reference numeral 311 indicates a flexure. A slider electrode 313 is provided at one end of the slider 309. The slider 309 is attached to the flexure 311, which is in the form of a thin plate, and a flexure electrode 315 of the flexure 311 extends so as to be at an angle of approximately 90 degrees with respect to the slider electrode 313. The soldering device for soldering such a workpiece is constructed as follows.
The soldering device is equipped with a conical suction nozzle 301 for conveying a solder ball 307 from a solder reservoir (not shown) to the electrodes to be soldered. The suction nozzle 301 is connected to a suction source (not shown), and the suction force from the suction source is applied to the solder ball 307 through a nozzle inner space 305 and a suction hole 303, and the solder ball 307 is held at the forward end of the suction nozzle 301 through suction. The solder ball 307 sucked by the suction nozzle 301 is held at a position where the solder ball 307 is in contact with the slider electrode 313 and the flexure electrode 315, and in this condition, is melted by a laser beam or the like (not shown). The melted solder ball is fixed in position between the slider electrode and the flexure electrode to effect electrical bonding between the two electrodes.
Recently, as magnetic heads are reduced in size, their electrodes are also becoming increasingly smaller. In the above-described soldering device 300, it is necessary to bring the forward end portion of the suction nozzle 301 close to the electrodes reliably and in a stable manner, with the solder ball 307 being sucked. However, as the electrodes and the peripheral members are reduced in size, it is becoming increasingly difficult to hold the solder ball 307 without unnecessarily bringing the forward end, etc. of the suction nozzle 301 into contact with the electrodes and the peripheral members. In view of this, another type of soldering device has been proposed. In the following, the construction of this other type of soldering device will be described.
FIG. 10 is a partial sectional view of the other type of soldering device. In this soldering device 400, a solid solder ball 407 is melted through heating, and is then ejected onto a substrate to effect soldering.
The soldering device 400 is equipped with a nozzle assembly 401 constituted by a nozzle 402 for ejecting the solder ball 407 and a nozzle main body 413 for holding the nozzle 402, a reservoir portion 415 for storing the plurality of the solder balls 407, and a laser device 417 for melting the solder balls 407. The nozzle 402 is tapered toward the distal end. Inside the nozzle 402, there are provided an accommodating portion 405 and an opening 403. The inner diameter of the portion of the accommodating portion 405 in the vicinity of the opening 403 is smaller than the outer diameter of the solder ball 407. The inner diameter of the rest of the nozzle accommodating portion 405 is larger than the outer diameter of the solder ball 407. Thus, the solid solder ball 407 guided to the accommodating portion 405 of the nozzle 402 is held inside the accommodating portion 405 at a position in the vicinity of the opening 403.
A laser beam from the laser device 417 is introduced into the accommodating portion 405 of the nozzle 402 through a laser introduction path 419 of the nozzle main body portion 413, and is applied to the solder ball 407 held in the vicinity of the opening 403 to melt the solder ball 407. Then, compressed gas from a compressed gas source (not shown) is supplied into the accommodating portion 405, thereby ejecting the molten solder ball 407.
In the soldering device 400, the solder ball 407 is melted inside the accommodating portion 405 of the nozzle 402, so that there is a fear of a portion or all of the molten solder ball 407 adhering to the inner wall surface of the accommodating portion 405 and the portion of the outer wall surface thereof around the opening 403. When, for example, the solder ball 407 adheres to the inner wall surface of the accommodating portion 405, a gap is generated between the next solder ball 407 introduced into the accommodating portion 405 and the inner wall surface of the accommodating portion 405, and compressed gas leaks through this gap, with the result that the proper inner pressure cannot be maintained within the accommodating portion, and the ejection of the molten solder ball may not be effected to a sufficient degree.
Further, at the time of ejection of the molten solder ball 407, the molten solder ball 407 is pulled by the surface tension of the molten solder member adhering to the inner wall surface, so that there is a fear of the molten solder ball being ejected in a direction deviated from the intended ejecting direction. Further, due to the adhering solder member, clogging may occur in the opening 403 of the nozzle 402.
To eliminate the above-mentioned problems, it is necessary to replace the contaminated nozzle or remove the solder member adhering to the inner wall surface and the outer wall surface of the nozzle 402.